When producing folded seam connections between partial surfaces of flat material closed in a tubular form or pipe segments, folding machines are used which comprise a machine stand, a fixed wheel, a pressing wheel which is able to displace in relation to the fixed wheel, and a closing disk which is displaceable in relation to the pressing wheel. In a first operation cycle, a flange-like outward extending brim or border is formed on each one of the pipe segments to be interconnected. To this end, matching folding wheels are used as a pressing wheel and a fixed wheel. In a second operation cycle, the pipe segments are joined to the two flange-like brims which are matching so as to achieve a folded seam connection. In particular, a single border is inserted into a double border, the double border being clamped together at individual locations. The, thus, assembled parts are put over the fixed wheel in such a manner that the joining region extends in its plane. For beading, the flange-like brim or the lower side of the double border engages the pressing wheel, and the closing disk is pressed or advanced step by step against a flange rim which projects somewhat in upward direction until the folded seam connection is completed. In this operation a substantially cylindrical disk is used as a fixed wheel, and a bearing disk as a pressing wheel. To rotate the pipe segments, either the fixed wheel and/or the pressing wheel may be driven. By a folding machine, lids or caps are attached to pipe segments in some cases.
From EP 104 145 a folding closure machine is known wherein a closing disk slide is supported by a rest so as to be parallel displaceable along a guide plate. The rest is mounted on a advance slide directly above the propping or pressing wheel. To exchange the pressing wheel or to use a folding wheel or a supporting disk in accordance with the operating cycle, the rest has to be detached, lifted off, put on again and fastened. This work is extremely troublesome, because the rest together with the closing disk slide are very heavy. Therefore, it is not efficient to use the machine alternately for both operation cycles mentioned above which, however, cannot be avoided with small series. Further disadvantages of the known approach consist in that the distance between the closing disk and the pressing wheel is not adjustable, and the pressing surface of the closing disk has always the same orientation, although the thickness of a folded seam connection and the orientation of the surface completely pressed by and facing the closing disk depend on the type of folded seam connection and on the flat material used. When using a closing disk which has always the same orientation, the difference in orientation of the surface to be pressed cannot be taken into account.